1. Field of the Invention:
The present invention relates to an endotracheal tube with a movable endobronchial blocker for one-lung anesthesia which is capable of accomplishing collapse of the operated lung with the usual technique for endotracheal intubation.
2. Description of the Prior Art:
Operations for lung cancer, esophageal cancer, thoracic aorta, etc. that need a thoracotomy are often disturbed by lung ventilation. Keeping such a lung depressed with a retractor may damage the lung. On the other hand, it has been confirmed by many researches, in the case of a patient who is certain to stand the aforesaid operations judging from his cardiopulmonary function, there is not any anesthetic trouble and danger during operation, even if the contralateral lung alone is ventilated, in other words even if the operated lung is completely collapsed. This technique is named "one-lung anesthesia". One-lung anesthesia can be of great assistance to the surgeon not only during operations on the lungs but also to provide better exposure for operations on the oesophagus, mediastinum and thoracic aorta.
Hitherto, one-lung anesthesia has been accomplished by the use of either single-lumen endobronchial tube which is placed in the main bronchus or double-lumen endobronchial tube invented by Carlens and Robertshaw. These tubes, however, have serious drawbacks and have not been used widely.
The conventional single-lumen endobronchial tube 11 is described with reference to FIG. 1-a and FIG. 1-b. The single-lumen endobronchial tube 11 is essentially a tube having cuffs 13 and 13'. It comes in two types: one for the left one-lung anesthesia (FIG. 1-a) and the other for the right one-lung anesthesia (FIG. 1-b). It is simple in structure, but has the following disadvantages.
(a) In order to accomplish the right one-lung anesthesia, it is necessary to position the end of the tube at the right main bronchus 17 as shown in FIG. 1-b. The branch-off point of the right upper lobe 19 is very close to the bifurcation of the trachea 15. In other words, the right main bronchus 17 is short (usually 1.5 cm or less) by nature. Therefore, there often arises an occasion that the end of the tube goes beyond the branch-off point of the right upper lobe 19, with the result that ventilation takes place only in the right middle and lower lobes of the right lung. In FIG. 1-b, the right middle bronchus, the right lower bronchus, and the intermediate bronchus are indicated by the reference numerals 21, 23 and 22, respectively. The left main bronchus, the left upper lobe bronchus, and the left lower lobe bronchus are indicated by the reference numerals 27, 29 and 31, respectively.
(b) Each time when it becomes necessary to inflate the collapsed lung during anesthesia, the tube 11 placed in the bronchus should be retracted to the trachea 15. And, after inflation of the operated lung, the tube should be inserted again into the main bronchus of the non-operated lung.
On the other hand, the double-lumen endobroncial tube is essentially a tube 33 integrally made up of a tube 33' for ventilating the right lung and a tube 33" for ventilating the left lung, the tube 33" being longer than the tube 33', as shown in FIG. 2. It was originally a rubber tube devised by Carlens for bronchospirometry, and it has the following disadvantages when used for one-lung anesthesia.
(a) Insertion requires a certain degree of skill.
(b) It is difficult to keep the tube fixed at a predetermined position, after insertion, and the tube often enters deep over the position or comes out during anesthesia. In other words, the tube is not stable.
In addition, the aforementioned two types of tubes have disadvantages by nature, the opening of the tubes being inevitably small in the inside diameter and the length of the tubes being long as compared with the endotracheal tube.